Anti spin-kick firearm

ABSTRACT

A firearm firing spin-stabilized projectiles having a barrel which can rotate or oscillate about its axis with respect to the receiver, said rotation or oscillation being constrained so that the reactive torque impacts resulting from the rapid spinning of the projectile during each discharge are smoothed out or applied to the receiver over a relatively long time in such manner that a very light weight, hand-held firearm firing automatically experiences negligible throw-off resulting from said torque impacts.

' States Patent 11 1 Robinson ANTI SPIN-KICK FIREARM 211 App]. No.: 79,377

1111 3,738,044 June 12, 1973 Primary Examiner-Benjamin A. Borchelt Assistant ExaminerC. T. Jordan [57] ABSTRACT A firearm firing spin-stabilized projectiles having a bar- [52] US. Cl. 42/75 B, 89/160 which can rotate or oscmate about its axis with f- F419 27/00,-F41d 11/00 spect to the receiver, said rotation 0r oscillation being [58] Field of Search 42/75 B; 89/160, constrained so that the reactive torque impacts result, 89/14 C ing from the rapid spinning of the projectile during each discharge are smoothed out or applied to the re- [56] References C'ted ceiver over a relatively long time in such manner that UNITED STATES PATENTS a very light weight, hand-held firearm firing automati- 936,369 10 1909 Searle 89/160 Cally experiences negligible throw-Off resulting from 1,459,285 6/1923 Declaye 42 75 B said torque impacts.

FOREIGN PATENTS OR APPLICATIONS -6 Claims, 4 Drawing Figures 308,572 10/1920 Germany 42/75 B 6 J 4 5 14. 3 I a fi tiles, each spun from one to 3,000 revolutions per second in very few milliseconds at most, produces a succession of reactive torque impactsin the firearm. In most single shot firing, said reactive torque impacts cannot be detected because of the heavy translational reaction of the firearm. When firing a very light weight, hand-held firearm automatically, however, said impacts can be detected by the firer and a tendancy occurs for the firearm to react in non-axial twisting pulses. Such pulses cause a throw-off which result in increased dispersion, thereby reducing accuracy of the firearm at moderate to extended ranges.

Should each such reactive torque impact be cushioned in such manner that said impact is applied to the receiver over a relatively long time, experience has 'shown that the deleterious effects of said reactive torque impacts are reduced. Should such cushioning be applied to the receiver at a reasonably constant torque level throughout almost the entire cyclic period, the deleterious effects of said impacts on accuracy appear to be virtually eliminated; The object of this invention is to cushion said reactive torque impacts.

Said object is realized by constructing a firearm for discharging spin-stabilized projectiles in such manner as to have a receiver, a longitudinally reciprocating forwardly spring-urged member which may comprise the breech bolt, bolt carrier, gas piston extension, slide, or any other member the longitudinal reciprocation of which occupies a relatively large portion of the cyclic period, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, said firearm also having means which changes the rate of rotation of said barrel with respect to said receiver through a period of time longer than the period of travel of said projectile through said barrel.

In a simple form of firearm according to the invention said means may comprise a snubbing device of a construction which provides a resilient or relatively low level torque connection disposed between said barrel and said receiver. Such a device may comprise a damped torque spring of well known construction or a friction motor which opposes the rotation of the barrel that occurs as a reaction to the torque impact of each shot, said device then bringing said barrel to rest with respect to said receiver in such manner that the application of the torque pulse to the receiver by the barrel as a result of each shot is spread over a considerably longer period than the period of shot travel and imparting of spin. t

In simple forms of the invention where such a snubbing device is used it may be difficult to adjust such device reliably to bring the barrel rotationally to rest in a reasonably extended portion of the period of each shot cycle in order to obtain a reasonable cushioning of said reactive torque impact.

In the preferred form of the invention absorption of the reactive torque impact throughout almost all of each full cyclic period is realized by constructing in the firearm a cam and follower formed in and cooperatively disposed between said barrel and said forwardly spring-urged member in such manner as to urge said barrel to rotate in the same sense as the projectile during counterrecoil of said member. It follows that said barrel would then rotate in the opposite sense to the projectile during recoil of said member. As said member translationally and rotationally accelerates during its counterrecoil movement and translationally and rotationally decelerates during its recoil movement owing to its forwardly spring-urged construction, the torque applied to said receiver by said member is in the same directional sense during both counterrecoil and recoil movements of said member.

A substantially continuous torque reaction is realized in firearms according to the preferred form of the invention by forming said cam and follower in such manner as to provide a' substantially constant angular acceleration to said barrel in the same sense as projectile rotation, as a result of the normal accelerated translational movement of said member.

Substantially constant torque reactions may furthermore be realized in firearms according to the preferred form of the invention by constructing same in such manner that the angular advance between said cam and follower is such with respect to the rotational inertia of the barrel that the sum of the rotational momentum of said barrel as said member reaches its maximum counterrecoil velocity plus that of said barrel as said member receives its maximum recoil velocity substantially equals that of the projectile as it leaves the barrel.

In some firearms according to the invention said member may be a rearward extension of a gas piston or a bolt carrier of such functioning that a short time dwell in the movement of said member occurs at its full counter recoil position and before recoil is imparted, Such a dwell would result in a brief interruption to the application of torque as described in the preferred example. In order to reduce the effects of such interruptions, the connecting support for said cam or the connecting support for said follower, or both said supports, may be formed in such manner as to be resilient.

The invention is further explained by reference to the following drawings in which:

FIG. 1 is a partial longitudinal section of the forward end of a firearm according to one form of the invention.

FIG. 2 is a view on the forward end of the example according to FIG. 1.

FIG. 3 is an oblique, partially sectioned view of the forward end of a firearm according to a preferred example of the invention, said end embodying all the relevant components of said firearm necessary fully to describe the invention.

FIG. 4 is a view on the forward of the example according to FIG. 3.

Referring to FIGS. 1 and 2, the firearm comprises a rifled barrel 1 having a cylindrical outer surface 2 with an enlarged diametral rim 3 formed at its rear end. Said barrel is supported in a hollow receiver 4 by a forward bearing 5 and by a rear grooved bearing 6 which are both formed in said receiver, grooved bearing 6 being provided with front and rear annular faces 7, 7 Said faces 7, 7 of bearing 6 cooperate with rim 3 of barrel 1 in such manner as to restrain said barrel from longitudinal movement with respect to receiver 4, but permit the unobstructed rotation of said barrel with respect to said receiver within the constraints of bearings 5 and 6.

The forward end of receiver 4 is formed with a forwardly protruding saddle 9 having transversely opposite lugs 10, 10' which lie in the horizontal plane and intersect an inner annular surface 11 formed in said saddle which is somewhat larger in radius than the radius of cylindrical portion 2 of barrel 1. A friction clip 12 having outwardly extending wings l3, l3 encircles barrel 1, one side of said clip being disposed in the annular space between barrel 1 and annular surface 11. Wings l3, 13 of clip 12 are provided with holes (not shown) which receive a tension screw 14. The threaded portion of screw 14 is threadedly accomodated in a vertical threaded hole 15 formed in lug 10 of saddle 9.

With the example constructed and assembled in the manner described it will be appreciated that the tightening of screw 14 increases the clamping action of clip 12 around barrel 1 in such manner that the torque resisting the rotation of barrel 1 with respect to receiver 4 is increased. With said screw tightened to a correct adjustment, however, the discharge of a shot results in the barrel being reactively spun by the projectile to an angular velocity in which its angular momentum, less losses due to friction, is equal but opposite to that imparted to the projectile. The clamping torque applied to said barrel is such as will then bringsaid barrel rotationally to rest with respect to receiver 4 in a period considerably longer than the period of projectile propulsion in the barrel. Accordingly, the reactive torque impact applied by the projectile has been absorbed by the barrel and reapplied to the receiver at a lower torque level and over a relatively longer time. Reduction of the torque level and its application to the receiver over a longer time results in the cushioning the effects of said reactive torque impact on said receiver.

Referring to FIG. 3, the second example is embodied in the forward portion of a machine pistol of well known blow-back or inertia-locked mode of operation and is shown in rearwardly seared or charged position. Said second example comprises a quasi-stationery receiver in which is formed a pair of opposite, longitudinally disposed guide ribs 21, 21; a bolt jacket 22 having support runners 23, 23 which slidably engage in said ribs in well known manner; a heavily precompressed spring or recuperator 24 which for purposes of the present example, is assumed to exert constant thrust throughout its full stroke and which is disposed in said receiver, the rear end of said recuperator thrusting against a transverse ledge 25 formed in said receiver, the forward end thrusting against the rear face of alug 26 formed under the front end of jacket 22; and a barrel 27 having an externally cylindrical body 28 and a circular rim 29 of larger diameter than said body formed at its rear end. Said barrel 27 is provided with internal rifling lands 30, 30 of well known form which, when viewed from the rear, progress forwardly in a clockwise sense, and also a plurality of external helical grooves 31, 31 formed into the forward portion of external cylinder 28 of said barrel which, when viewed from the rear, progress forwardly in a counter clockwise sense. The rate of advance of 'grooves 31, 31 is such with respect to the angular inertia of barrel 27 as to provide the angular momentum'requirements described below. Said barrel 27 is slidably supported in jacket 22 by a short forward bearing 32 formed in said jacket 22 and by a rear bearing annulus 33 which is formed in ledge 25 of receiver 20 in a manner similar to that of the example of FIGS. 1 and 2, said annulus slidably receiving the rim 29 of barrel 27. Both bearing 32 and annulus 33 function in such manner as to restrain barrel 27 against longitudinal movement with respect to receiver 20 but to permit free rotation of said barrel within and with respect to said receiver. Helical risers 34, 34' are formed in bearing 32 of jacket 22 which slidably mate with grooves 31, 31 formed in barrel 27, the cooperation between said risers and said grooves being such that as jacket 22 is reciprocated, barrel 27 is constrained to rotate oscillatably. It will be noted that grooves 31, 31 formed in barrel 27 are constructed to be sufficiently long to provide for the full normal reciprocation of jacket 22 without disengaging from risers 34, 34 formed in said jacket.

With the relevant components of the example constructed and assembled in the manner described, when the sear (not shown) which restrains jacket 22 rearwardly in well known manner is released, said jacket is accelerated forwardly under the influence of recuperator 24 at a substantially constant linear acceleration. Simultaneously the risers 34, 34' of bearing 32 of said jacket acting in grooves 31, 31 of barrel 27 cause said barrel to rotate in a clockwise sense at a substantially constant angular acceleration, the torque reaction applied to receiver 20 as a result of said rotational acceleration of said barrel being applied via jacket 22 being in a counter clockwise sense. Upon chambering and discharge of the cartridge by well known means beyond the scope of this invention as jacket 22 reaches its forward limit of travel with respect to receiver 20 and bar rel 27, said barrel has had imparted to it in the manner described an angular velocity in clockwise sense such that the rotational momentum of said barrel is substan tially one half that of the clockwise rotating bullet at the moment when said bullet leaves the barrel 27. Reaction in barrel 27 to the spinning of the projectile, due to the law of conservation of momentum, is sufficient to arrest the said clockwise rotation imparted to barrel 27 and to impart an approximately equal angular velocity'to said barrel in the opposite or counter clockwise sense. At substantially the same instant the full linear recoil velocity is imparted to jacket 22 due to the translational reaction to the discharge. As jacket 22 recoils it is linearly decelerated by forward thrust of the recuperator 24, said translational deceleration resulting in an angular deceleration of barrel 27, the rotational reaction to said angular deceleration also being in the counter clockwise direction.

In short, the example according to the invention operates in such manner that a low level counter clockwise reaction in one sense only is applied to receiver 20 during both forward acceleration and rearward deceleration of jacket 22. Accordingly the reactive torque impact imparted by the projectile to the firearm is replaced by a small unidirectional torque applied by jacket 22 to receiver 20 as said jacket reciprocates and causes oscillation of barrel 27, said torque extending virtually throughout each cyclic period.

Referring to FIG. 4, the example shown thereon refers particularly to a type of firearm according to the invention in which a short time dwell occurs in the movement of bolt jacket 22 after it has completed its counter recoil movement and before it receives its recoil movement. According to this example front bearing 32 of jacket 22 together with channels 34, 34' are formed in a nut 35 which is bonded by vulcanizing to a ring 36 formed of resilient material such as synthethic rubber The external surface of ring 36 is somewhat larger in diameter than a coaxial hole 37 formed in the forward end of said jacket. Ring 36 is then interferably pressed into hole 37. In alternative constructions according to this example wherein said dwell is of exceedingly short time duration it will be noted that the external surface of ring 36 may be bonded by vulcanizing into hole 37 Having disclosed and described the invention, what I claim is:

l. A firearm for discharging spin-stabilized projectiles,,said firearm having a receiver, a longitudinally reciprocating forwardly spring-urged member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, said firearm also having means which changes the rate of rotation of said barrel through a period of time longer than the period of travel of said projectile through said barrel.

2. A fire arm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating forwardly spring-urged member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, said firearm also having a snubbing device which brings said barrel rotationally to rest with respect to said receiver in such manner that the application of torque to said receiver by said barrel is spread over a longer period than the period of travel of said projectile in said barrel.

3. A firearm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating member which is forwardly spring-urged to provide accelerated translational movement to said member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, and a cam and follower cooperatively disposed between said barrel and said member in such manner as to urge said barrel to rotate in the same sense as said projectile is caused to rotate by said rifled barrel during the counterrecoil movement of said member.

4. A firearm according to claim 3 in which said cam is formed in such manner as to provide a substantially constant angular acceleration to said barrel as a result of the normal accelerated translational movement of said member.

5. A firearm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating member which is forwardly spring-urged to provide accelerated translational movement to said member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, and a cam and follower cooperatively disposed between said barrel and said member in such' manner as to urge said barrel to rotate in the same sense as said projectile is caused to rotate by said rifledbarrel during the counterrecoil movement of said member, and in which the angular advance between said cam and said follower is such that the sum of rotational momentum imparted to said barrel as said member reaches its maximum counterrecoil velocity plus that imparted to said barrel as said member receives its maximum recoil velocity following discharge of a shot substantially equals that of each said projectile as same exits said barrel.

6. A firearm according to claim 3 in which a connecting support for said cam and follower is formed in such manner as to be resilient. 

1. A firearm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating forwardly spring-urged member, a riFled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, said firearm also having means which changes the rate of rotation of said barrel through a period of time longer than the period of travel of said projectile through said barrel.
 2. A fire arm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating forwardly spring-urged member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, said firearm also having a snubbing device which brings said barrel rotationally to rest with respect to said receiver in such manner that the application of torque to said receiver by said barrel is spread over a longer period than the period of travel of said projectile in said barrel.
 3. A firearm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating member which is forwardly spring-urged to provide accelerated translational movement to said member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, said barrel being caused to rotate by torque reaction of each said projectile discharged through same, and a cam and follower cooperatively disposed between said barrel and said member in such manner as to urge said barrel to rotate in the same sense as said projectile is caused to rotate by said rifled barrel during the counterrecoil movement of said member.
 4. A firearm according to claim 3 in which said cam is formed in such manner as to provide a substantially constant angular acceleration to said barrel as a result of the normal accelerated translational movement of said member.
 5. A firearm for discharging spin-stabilized projectiles, said firearm having a receiver, a longitudinally reciprocating member which is forwardly spring-urged to provide accelerated translational movement to said member, a rifled barrel supported in such manner as to be able to rotate with respect to said receiver about an axis substantially coaxial with the axis of said barrel, and a cam and follower cooperatively disposed between said barrel and said member in such manner as to urge said barrel to rotate in the same sense as said projectile is caused to rotate by said rifled barrel during the counterrecoil movement of said member, and in which the angular advance between said cam and said follower is such that the sum of rotational momentum imparted to said barrel as said member reaches its maximum counterrecoil velocity plus that imparted to said barrel as said member receives its maximum recoil velocity following discharge of a shot substantially equals that of each said projectile as same exits said barrel.
 6. A firearm according to claim 3 in which a connecting support for said cam and follower is formed in such manner as to be resilient. 